Program Introduction and Statement of Objectives In accordance with the instructions set forth in RFA-NS-08-004, we are submitting a Research Center of Excellence (RCE) application entitled: "Novel Treatments of Chlorine Induced Injury to the Cardio- Respiratory Systems". The main purpose of this Research Center of Excellence is to integrate the efforts of highly productive investigators from two leading institutions (University of Alabama at Birmingham and Yale University) with diverse and complimentary expertise on airway biology, neurosensory control of airway function, environmental pulmonary toxicology, free radical biochemistry, ion channel electrophysiology, vascular biology, aerosol physics, and drug development. The overall goal is to test new treatment strategies involving FDA approved agents or newly developed drugs currently undergoing clinical trials, which when administered post exposure are capable of reversing CI2 induced injury to lung epithelia and pulmonary and systemic vasculatures in both healthy and individuals with pre-existing lung diseases. The RCE germinated during the first meeting of the CounterAct Network when Dr. Matalon and Jordt met, discussed their research, and upon discovering many common interests, decided to collaborate. We agreed that there was a need to investigate the effects of chlorine exposure on animals with pre-existing lung diseases. We decided to concentrate on two diseases affecting large fractions of the adult and pediatric populations: Asthma and Respiratory Syncytial Virus Infections. The following seminal observations, made by members of this highly integrated team, formed the rational basis for proposed research in the RCE. [unreadable] Exposure of rats and mice to CI2 gas in concentrations likely to be encountered during industrial accidents or chemical warfare depletes ascorbate and reduced glutathione in the lung epithelial lining fluid rendering airway and alveolar epithelial cells defenseless to a subsequent oxidant insult. This observation provides the rationale for the use of ascorbate and N-acetylcysteine (both FDA approved for human use) as post CI2 exposure therapeutics. [unreadable] CI2 stimulates excitatory airway neurons leading to respiratory depression, broncho-constriction, increased mucous production and airway obstruction. In a seminal series of experiments, Dr. Jordt showed that these events are initiated by activation of ion channel TRPA1 (Transient Receptor Potential Ankyrin 1) by CI2 derived reactive intermediates. These observations provide the basis for the proposed use of TRPA1 channel antagonists and antioxidants to deactivate TRPA1 and other TRP channels thus limiting CI2 induced lung injury and airway irritation. [unreadable] CI2 inhalation damages alveolar epithelial cells decreasing their ability to actively transport sodium ions and prevent the entry of plasma proteins in the alveolar space. This results in the formation of protein rich alveolar edema and respiratory failure. This observation provides the rational basis for the use of short and long term acting /?2 agonists along with antioxidants to activate alveolar fluid clearance and at the same time reverse airway constriction. [unreadable] Seminal observations by investigators in Project 3 show that inhalation of oxidant gases damages not only respiratory and alveolar epithelial but the pulmonary and systemic vasculatures as well. These events are the consequence of inactivation of the eNOS signaling pathway which may lead to acceleration of vascular diseases such as atherosclerosis. This observation sets the rational basis for the use of nitrite as an eNOS independent source of nitric oxide, thus improving vascular tone and limiting inflammation and cytotoxicity. Indeed, exciting preliminary data generated by collaborative efforts between Dr. Patel and Matalon, and shown in Projects 1 and 3, provide the first evidence that post CI2-administration of nitrite, an agent approved by the FDA for human use, significantly decreases CI2 induced lung injury. [unreadable] Infections of mice with Respiratory Syncytial Virus, an agent which infects all age groups and in particular children and the elderly, decreases alveolar fluid clearance, increases steady state concentrations of reactive species in the lungs, and causes mild hypoxemia and pulmonary edema. This observation, along with studies in the literature, showing that animals and patients with mild lung PHS 398/2590 (Rev. 09/04, Reissued 4/2006) Page 102 Continuation Format Page Principal Investigator/Program Director (Last, First, Middle): MatalOD, SadJS disease are highly sensitive to subsequent oxidant stress, highlights the importance of carefully documenting how vulnerable populations respond to CI2 inhalation. [unreadable] Existing evidence in the literature and Dr. Jordt's recent observations, indicate that patients with asthma develop severe bronchoconstriction even when exposed to very low (thought to be innocuous) concentrations of CI2. Dr. Jordt hypothesizes that asthma and the existing inflammatory response senstitizes TRPA1 channels, increasing their responses to a subsequent CI2 exposure. These observations provide the rational basis for testing the response of animal models with airway hypersensitivity to CI2. It is worthwhile to point out that RSV infections predispose children to the development of asthma. In summary: (1) we are extending previous seminal observations from two existing UO1s (Drs. Jordt and Matalon) to assess CI2toxicity in vulnerable populations;(2) we have recruited an outstanding young but highly accomplished investigator who already has made seminal observations on the use of nitrite as a therapeutic agent in correcting ischemia-reperfusion;(3) we are proposing to establish an integrated regiment of therapeutic agents consisting of antioxidants;nitrite, TRP Channel antagonists and 02 agonists for the treatment of CI2 induced injury to the pulmonary and systemic systems in both normal animals and those with pre-existing lung disease.